Photosensitive resin plates used in the manufacture of relief printing plates are developed by washing with water and/or organic solvents. Once development of exposed plates (i.e., washing to remove unexposed resin therefrom) is complete, it is desirable to remove residual solvent from the exposed resin prior to further processing of the resin plate. Failure to do so will compromise the integrity of the plate upon final curing, for example by cracking, fracturing, shrinking, warping, etc., and lead to poor print quality if the plate is not sufficiently dried.
Currently, thermal convection ovens are employed in the art for such purpose. There are, however, numerous drawbacks to the present methods employed for drying solvent-containing resins. For example, present methods are highly energy inefficient, since the entire resin plate is heated in efforts to drive off solvent (instead of selectively heating only that portion of the resin which is targeted for solvent removal), convection ovens have long heat-up and cool-down cycles, ovens must be maintained at an elevated temperature for extended periods of time if rapid drying on demand is desired, very large ovens (with the associated space and utility requirements) are necessary when continuous drying processes are contemplated, and the like. In addition, there is a substantial potential for exposing the resin to excessive levels of heat in efforts to achieve an acceptable level of drying. Such exposure can have a variety of detrimental effects on resin performance, e.g., degradation of the polymeric resin, cracking of the resin, curling of the resin plate, and the like.
Accordingly, what is needed in the art are more energy efficient methods than are currently available for removing diluent from polymeric resin materials. Especially useful would be methods for removing diluent from polymeric resin materials without compromising the chemical and physical properties of said resin.